It showed up in a N.Y. Times Maureen Dowd column this morning, and I don't know that I had ever see the word before...though it dates to the 1600's!
"mendaciousness"----Can you guess who Dowd was describing when she used it?
[ men-dey-shuhs ]
telling lies, especially habitually; dishonest; lying; untruthful: a mendacious person.
false or untrue: a mendacious report.